Link Multiple field with Primary

Sometimes you have a hasMany relationship and need to have the ability to a select primary record among related ones. As example, a Contacts field of the Case entity.

Need to create a contacts linkMultiple field with a primary for our custom entity Stock.

Step 1

Create (or edit) custom/Espo/Custom/Resources/metadata/entityDefs/Stock.json:

json { "fields": { "contacts": { "type": "linkMultiple", "view": "custom:views/stock/fields/contacts" }, "contact": { "type": "link" } }, "links":{ "contact": { "type": "belongsTo", "entity": "Contact", "foreign": "stocksPrimary" }, "contacts": { "type": "hasMany", "entity": "Contact", "foreign": "stocks", "layoutRelationshipsDisabled": true } } }

Step 2

custom/Espo/Custom/Resources/metadata/entityDefs/Contact.json

json { "links":{ "stocksPrimary": { "type": "hasMany", "entity": "Stock", "foreign": "contact", "layoutRelationshipsDisabled": true }, "stocks": { "type": "hasMany", "entity": "Stock", "foreign": "contacts" } } }

Step 3

custom/Espo/Custom/Hooks/Stock/AfterSave.php

```php <?php namespace Espo\Custom\Hooks\Stock;

use Espo/ORM/Entity; use Espo/ORM/EntityManager;

class AfterSave { public function __construct(private EntityManager $entityManager) {}

public function afterSave(Entity $entity, array $options): void
{            
    if (!$entity->isAttributeChanged('contactId')) {
        return;
    }

    $contactId = $entity->get('contactId');
    $fetchedContactId = $entity->getFetched('contactId');

    $relation = $this->entityManager
        ->getRDBRepository($entity->getEntityType())
        ->getRelation($entity, 'contacts');

    if (!$contactId) {
        $relation->unrelateById($fetchedContactId);

        return;
    }

    $relation->relateById($contactId);        
}

} ```

Step 4

client/custom/src/views/stock/fields/contacts.js

js define(['views/fields/link-multiple-with-primary'], (Dep) => { return class extends Dep { primaryLink = 'contact' } });

Step 5

Run Rebuild.

Step 6

Execute an SQL query:

sql UPDATE stock JOIN contact_stock ON contact_stock.stock_id = stock.id AND contact_stock.deleted = 0 SET stock.contact_id = contact_stock.contact_id